Hi Fred 94,
I agree with sonavor- the wattage numbers is only a part of the story. The efficiency of the speakers comes into it i.e.high efficiency speakers need less amplifier power while low efficiency speakers need a lot more power.
I'm not familiar with the RL140,but I would be very surprised if they needed more than the 4500's 55wattsper channel to "perform" properly.
I'm running a 4500 with JBL speakers that are rated at 80 watts, and there's no sense of "not enough power". In fact ,the danger of not having enough headroom in the amp is if it's maximum power output starts to "clip" i.e. distortion,and speakers definitely don't like square waves.Result ? blown speakers.
But with the Beomasters, there is a built-in safety net.
The 2 x 55 watt/8 ohm amplifier had a newly-developed, well-balanced interplay with the power supply which gave the output extra strength. The power reserve encompassed the entire frequency range and gave stable sound quality no matter what the volume. Beomaster 4500 also had automatic power handling control that prevented overloading, no matter how many loudspeakers were connected.
regards
Noel.